• Title/Summary/Keyword: Shock Mechanism

Search Result 357, Processing Time 0.021 seconds

Traditional and Novel Mechanisms of Heat Shock Protein 90 (HSP90) Inhibition in Cancer Chemotherapy Including HSP90 Cleavage

  • Park, Sangkyu;Park, Jeong-A;Jeon, Jae-Hyung;Lee, Younghee
    • Biomolecules & Therapeutics
    • /
    • v.27 no.5
    • /
    • pp.423-434
    • /
    • 2019
  • HSP90 is a molecular chaperone that increases the stability of client proteins. Cancer cells show higher HSP90 expression than normal cells because many client proteins play an important role in the growth and survival of cancer cells. HSP90 inhibitors mainly bind to the ATP binding site of HSP90 and inhibit HSP90 activity, and these inhibitors can be distinguished as ansamycin and non-ansamycin depending on the structure. In addition, the histone deacetylase inhibitors inhibit the activity of HSP90 through acetylation of HSP90. These HSP90 inhibitors have undergone or are undergoing clinical trials for the treatment of cancer. On the other hand, recent studies have reported that various reagents induce cleavage of HSP90, resulting in reduced HSP90 client proteins and growth suppression in cancer cells. Cleavage of HSP90 can be divided into enzymatic cleavage and non-enzymatic cleavage. Therefore, reagents inducing cleavage of HSP90 can be classified as another class of HSP90 inhibitors. We discuss that the cleavage of HSP90 can be another mechanism in the cancer treatment by HSP90 inhibition.

Ready-Made Garments (RMG) Export Earnings and Economic Development of Bangladesh: Empirical Analysis Using Vector Error Correction Model

  • JIBAN, Abul Jannat;BISWAS, Gautam Kumar;YANG, Shaohua
    • The Journal of Asian Finance, Economics and Business
    • /
    • v.9 no.10
    • /
    • pp.29-38
    • /
    • 2022
  • Ready-made Garments (RMG) export earnings, which are almost 80% of the total exports of Bangladesh, have been recognized as one of the main catalysts for the recent development of the country. Therefore, the need to determine whether the RMG export had served as a mechanism for increasing the GDP growth as well as the economic development of the country is topical and pressing. We have applied the Johansen Co-integration test and Vector Error Correction Model (VECM) to reveal the linkage of RMG export earnings and other variables with the GDP growth rate in Bangladesh. Using data from 1990 to 2020 for Bangladesh, we have found long-run as well as short-run associations among RMG Export earnings, Foreign Direct Investment (FDI), and GDP growth. A co-integration among the variables is validated through the Johansen Co-integration test. Moreover, a causal correlation running from RMG export earnings to GDP was revealed by the Granger causality test in the long run. Finally, we estimated impulse response functions to observe the variations of model variables in response to a shock. Our result supports the proposition that RMG export earnings are one of the main growth engines in Bangladesh and this sector leads growth in other sectors also in the long term.

Anisomycin protects against sepsis by attenuating IκB kinase-dependent NF-κB activation and inflammatory gene expression

  • Park, Gyoung Lim;Park, Minkyung;Min, Jeong-Ki;Park, Young-Jun;Chung, Su Wol;Lee, Seon-Jin
    • BMB Reports
    • /
    • v.54 no.11
    • /
    • pp.545-550
    • /
    • 2021
  • Anisomycin is known to inhibit eukaryotic protein synthesis and has been established as an antibiotic and anticancer drug. However, the molecular targets of anisomycin and its mechanism of action have not been explained in macrophages. Here, we demonstrated the anti-inflammatory effects of anisomycin both in vivo and in vitro. We found that anisomycin decreased the mortality rate of macrophages in cecal ligation and puncture (CLP)- and lipopolysaccharide (LPS)-induced acute sepsis. It also declined the gene expression of proinflammatory mediators such as inducible nitric oxide synthase, tumor necrosis factor-α, and interleukin-1β as well as the nitric oxide and proinflammatory cytokines production in macrophages subjected to LPS-induced acute sepsis. Furthermore, anisomycin attenuated nuclear factor (NF)-κB activation in LPS-induced macrophages, which correlated with the inhibition of phosphorylation of NF-κB-inducing kinase and IκB kinase, phosphorylation and IκBα proteolytic degradation, and NF-κB p65 subunit nuclear translocation. These results suggest that anisomycin prevented acute inflammation by inhibiting NF-κB-related inflammatory gene expression and could be a potential therapeutic candidate for sepsis.

The Effect of the COVID-19 Pandemic on Stock Market Returns in Emerging Economies: Empirical Evidence from Panel Data

  • GNAHE, Franck Edouard;ASHRAF, Junaid;HUANG, Fei-Ming
    • The Journal of Asian Finance, Economics and Business
    • /
    • v.9 no.4
    • /
    • pp.191-196
    • /
    • 2022
  • From several socioeconomic perspectives, the present health crisis can be connected to the 2008 financial and economic catastrophe. Governments worldwide are working hard to keep the markets in check, as evidence suggests that the health crisis may soon become an economic crisis. This paper aims to analyze the effect of COVID-19 on the selected stock market. Using a panel of daily COVID-19 confirmed cases and deaths and the stock market from 22 developing countries, we exploit an oil price as a shock to the stock market and examine the effect of COVID-19 on the slowdown of the stock market. We find a negative and significant impact of COVID-19 on the stock market in the first stage till April. However, there is no net influence on the stock market downturn when we extend the period. However, further study suggests that the outbreak's negative influence on the selected stock market has diminished and has begun to decline as of mid-April. As a result of the COVID-19 effect on the chosen stock, our findings imply that the government in the chosen market should consider a regulatory mechanism to reduce the stock market slowdown induced by the pandemic COVID-19.

Intensive Monitoring Survey of Nearby Galaxies (IMSNG) : On the progenitor system of Type Ia SN 2018kp

  • Choi, Changsu;Im, Myungshin;Kim, Dohyeong;Lim, Gu;Paek, Gregory S.H.;Kim, Sophia;Hwang, Sungyong
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.45 no.1
    • /
    • pp.36.2-36.2
    • /
    • 2020
  • Intensive Monitoring Survey of Nearby Galaxies (IMSNG) has been managed over 6 years. It aimed to constrain the progenitor system and explosion mechanism of SNe by detection of very early signal from shock heated emission. We have conducted monitoring observation of nearby bright galaxies those were carefully selected using global network of 1-m class telescopes. More than 20 SNe have occured in our target fields. As One of result of the survey, we present light curve analysis of type Ia SN 2018kp, which was discovered in NGC 3367. Based on photometric analysis, we calculated explosion parameters and set constraints of physical conditions of this supernova. We compared the results with theoretical model progenitor systems to find out which scenario is the most fitted to SN 2018kp case. Moreover, we estimate the distance to the galaxy and look into the relation between SNe and galactic physical parameters.

  • PDF

Current Status of Intensive Monitoring Survey of Nearby Galaxies and Core-Collapse Supernovae Observational Research

  • Kim, Sophia;Im, Myungshin;Choi, Changsu;Im, Gu;Paek, Gregory S.
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.46 no.2
    • /
    • pp.80.1-80.1
    • /
    • 2021
  • Intensive Monitoring Survey of Nearby Galaxies (IMSNG) is a program monitoring nearby galaxies with a high cadence within a day. The main goal of the project is to constrain the SNe explosion mechanism and properties of their progenitors by catching the early lights from the shock-heated cooling emission. The observation campaign began in 2014 with two 1-m class telescopes in the northern hemisphere. Now more than ten telescopes are monitoring galaxies with 60 IMSNG targets, which have a high probability of supernova explosion every night all around the world. Since the project started, the following observations have been carried out on 14 SNe Ia(including -pec), 27 core-collapse supernovae (CCSNe), and around 40 transients in other types. In this poster, we present the current status of IMSNG SNe data first and then focus more on the CCSNe. CCSNe are the explosion of massive stars, more massive than eight times of the Sun. They have been studied for more than a half decades but still have key questions to be solved, such as distinct types, the characteristics driving their diversity, and so on. Here, we show our ongoing studies of CCSNe in IMSNG, focusing on their usefulness as distance indicators and properties of early light curves.

  • PDF

Transcriptome and Small RNAome Analyses Reveal the Association of pre-harvest Sprouting and Heat Stress Response in Rice (Oryza sativa L.)

  • Minsu Park;Woochang Choi;Sang-Yoon Shin;Yujin Kweon;Jihyun Eom;Minsun Oh;Chanseok Shin
    • Proceedings of the Korean Society of Crop Science Conference
    • /
    • 2023.04a
    • /
    • pp.157-157
    • /
    • 2023
  • Pre-harvest sprouting (PHS) in rice (Oryza sativa L.) is one of the main problems associated with seed dormancy. PHS causes yield loss and reduction of grain quality under unpredictable humid conditions at the ripening stage, thus affecting the economic value of the rice crop. To resolve this issue, it is important to understand the molecular mechanism underlying seed dormancy in rice. Recent studies have shown that seed dormancy is affected by a large number of genes associated with plant hormones. However, the effect of heat stress on seed dormancy and plant hormones is not well understood. In this study, we compared the PHS rate as well as the transcriptome and small RNAome of the seed embryo and endosperm of two different accessions of rice, PHS-susceptible rice (low dormancy) and PHS-resistant rice (high dormancy) under three different maturation stages. We identified and verified the candidate genes associated with seed dormancy and heat stress-related responses in rice using quantitative real-time PCR. We newly discovered hormone-related genes, heat shock protein-related genes, and miRNAs potentially involved in PHS. These findings provide a foundation for understanding the dynamics of transcriptome and small RNAome of hormone- and heat stress-related genes, which affect PHS during seed maturation.

  • PDF

Polygonatum sibiricum component liquiritigenin restrains breast cancer cell invasion and migration by inhibiting HSP90 and chaperone-mediated autophagy

  • Suli Xu;Zhao Ma;Lihua Xing;Weiqing Cheng
    • The Korean Journal of Physiology and Pharmacology
    • /
    • v.28 no.4
    • /
    • pp.379-387
    • /
    • 2024
  • Breast cancer (BC) is most commonly diagnosed worldwide. Liquiritigenin is a flavonoid found in various species of the Glycyrrhiza genus, showing anti-tumor activity. This article was to explore the influences of liquiritigenin on the biological behaviors of BC cells and its underlying mechanism. BC cells were treated with liquiritigenin alone or transfected with oe-HSP90 before liquiritigenin treatment. RT-qPCR and Western blotting were employed to examine the levels of HSP90, Snail, E-cadherin, HSC70, and LAMP-2A. Cell viability, proliferation, migration, and invasion were evaluated by performing MTT, colony formation, scratch, and Transwell assays, respectively. Liquiritigenin treatment reduced HSP90 and Snail levels and enhanced E-cadherin expression as well as inhibiting the proliferation, migration, and invasion of BC cells. Moreover, liquiritigenin treatment decreased the expression of HSC70 and LAMP-2A, proteins related to chaperone-mediated autophagy (CMA). HSP90 overexpression promoted the CMA, invasion, and migration of BC cells under liquiritigenin treatment. Liquiritigenin inhibits HSP90-mediated CMA, thereby suppressing BC cell growth.

Working Mechanism of Peroxiredoxins (Prxs) and Sulphiredoxin1 (Srx1) in Arabidopsis thaliana (애기장대 peroxiredoxins (Prxs)과 sulphiredoxin1 (Srx1)의 작용기작)

  • Kim, Min-Gab;Su'udi, Mukhamad;Park, Sang-Ryeol;Hwang, Duk-Ju;Bae, Shin-Chul
    • Journal of Life Science
    • /
    • v.20 no.12
    • /
    • pp.1777-1783
    • /
    • 2010
  • Plants generate reactive oxygen species (ROS) as a by-product of normal aerobic metabolism or when exposed to a variety of stress conditions, which can cause widespread damage to biological macromolecules. To protect themselves from oxidative stress, plant cells are equipped with a wide range of antioxidant proteins. However, the detailed reaction mechanisms of these are still unknown. Peroxiredoxins (Prxs) are ubiquitous thiol-containing antioxidants that reduce hydrogen peroxide with an N-terminal cysteine. The active-site cysteine of peroxiredoxins is selectively oxidized to cysteine sulfinic acid during catalysis, which leads to inactivation of peroxidase activity. This oxidation was thought to be irreversible. Recently identified small protein sulphiredoxin (Srx1), which is conserved in higher eukaryotes, reduces cysteine.sulphinic acid in yeast peroxiredoxin. Srx1 is highly induced by $H_2O_2$-treatment and the deletion of its gene causes decreased yeast tolerance to $H_2O_2$, which suggest its involvement in the metabolism of oxidants. Moreover, Srx1 is required for heat shock and oxidative stress induced functional, as well as conformational switch of yeast cytosolic peroxiredoxins. This change enhances protein stability and peroxidase activity, indicating that Srx1 plays a crucial role in peroxiredoxin stability and its regulation mechanism. Thus, the understanding of the molecular basis of Srx1 and its regulation is critical for revealing the mechanism of peroxiredoxin action. We postulate here that Srx1 is involved in dealing with oxidative stress via controlling peroxiredoxin recycling in Arabidopsis. This review article thus will be describing the functions of Prxs and Srx in Arabidopsis thaliana. There will be a special focus on the possible role of Srx1 in interacting with and reducing hyperoxidized Cys-sulphenic acid of Prxs.

Lightweight Aggregate Bloating Mechanism of Clay/Incinerated Ash/Additive System (점토/소각재/첨가제계 인공 경량골재의 발포기구)

  • Kwon, Yong-Joon;Kim, Yoo-Taek;Lee, Ki-Gang;Kim, Young-Jin;Kang, Seung-Gu;Kim, Jung-Hwan;Park, Myoung-Sik
    • Journal of the Korean Ceramic Society
    • /
    • v.38 no.9
    • /
    • pp.811-816
    • /
    • 2001
  • The influence of the incinerated ash and additives on glass phase formation of lightweight aggregate, weight-lightening, and the bloating mechanism was investigated. Clay was used as base materials and incinerated ash was added from 0 to 30wt%. The additives such as $Na_2CO_3,\;CaCo_3,\;K_2CO_3,\;MgCO_3$, and a little amount of waste oil were added to the mixed body. In clay/incinerated ash/additive system, it turned out that $CaCO_3\;and\;MgCO_3$ were the components for glass phase formation and $Na_2CO_3$ was the component for both glass phase formation and weight-lightening. The small addition of waste oil from 0.5wt% to 3.0wt% affect on the bloating of aggregate. Incinerated ash had a good effect on the glass phase controlling. The most effective condition controlling glass phase and bloating of aggregate was 10wt% incinerated ash, 2wt% waste oil at 1200$^{\circ}$C. The bloating mechanism of lightweight aggregate is as follows; 1) micro-crack formation caused by thermal-shock and gas generation from inside of aggregate, 2) volume expansion by glass phase formation on the aggregate surface and rapid gas bloating inside of aggregate, 3) densification after bloating.

  • PDF